U.S. patent number 10,415,250 [Application Number 14/760,856] was granted by the patent office on 2019-09-17 for liquid-applied waterproofing membrane comprising oxazolidine and aldimine.
This patent grant is currently assigned to SIKA TECHNOLOGY AG. The grantee listed for this patent is Sika Technology AG. Invention is credited to Urs Burckhardt, Michael Byrne, Alexander Coward, Mark Gatrell.
United States Patent |
10,415,250 |
Byrne , et al. |
September 17, 2019 |
Liquid-applied waterproofing membrane comprising oxazolidine and
aldimine
Abstract
The present invention describes a one-part moisture-curing
liquid-applied waterproofing membrane including a polyurethane
polymer and both an aldimine and an oxazolidine as blocked amine
hardeners in a specific ratio range. The membrane has a low odor, a
long shelf life stability, a low viscosity at low solvent content,
a sufficiently long open time to allow hand application and cures
fast to a solid elastic material. The liquid-applied waterproofing
membrane can be suitable for roofing applications, possessing high
strength, high elongation and good durability under outdoor
weathering conditions in a broad temperature range.
Inventors: |
Byrne; Michael (Lytham,
GB), Gatrell; Mark (Chipping Preston, GB),
Coward; Alexander (Sale, GB), Burckhardt; Urs
(Zurich, CH) |
Applicant: |
Name |
City |
State |
Country |
Type |
Sika Technology AG |
Baar |
N/A |
CH |
|
|
Assignee: |
SIKA TECHNOLOGY AG (Baar,
CH)
|
Family
ID: |
47720281 |
Appl.
No.: |
14/760,856 |
Filed: |
January 21, 2014 |
PCT
Filed: |
January 21, 2014 |
PCT No.: |
PCT/EP2014/051135 |
371(c)(1),(2),(4) Date: |
July 14, 2015 |
PCT
Pub. No.: |
WO2014/114640 |
PCT
Pub. Date: |
July 31, 2014 |
Prior Publication Data
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|
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Document
Identifier |
Publication Date |
|
US 20160024318 A1 |
Jan 28, 2016 |
|
Foreign Application Priority Data
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|
|
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Jan 22, 2013 [EP] |
|
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13152262 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B05D
1/40 (20130101); E04D 11/02 (20130101); C08G
18/307 (20130101); C08G 18/10 (20130101); C08G
18/3256 (20130101); E04D 7/00 (20130101); C09D
7/20 (20180101); B32B 5/028 (20130101); C09D
175/04 (20130101); C08G 18/503 (20130101); B32B
2307/7265 (20130101); B32B 2260/046 (20130101); B32B
2419/06 (20130101) |
Current International
Class: |
E04D
7/00 (20060101); B32B 5/02 (20060101); C08G
18/32 (20060101); C09D 7/20 (20180101); C08G
18/50 (20060101); C08G 18/30 (20060101); C08G
18/10 (20060101); B05D 1/40 (20060101); C09D
175/04 (20060101); E04D 11/02 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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101309898 |
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Nov 2008 |
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CN |
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101312942 |
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Nov 2008 |
|
CN |
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101484491 |
|
Jul 2009 |
|
CN |
|
2 017 260 |
|
Jan 2009 |
|
EP |
|
2 236 534 |
|
Oct 2010 |
|
EP |
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9-286836 |
|
Nov 1997 |
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JP |
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2007-332257 |
|
Dec 2007 |
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JP |
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2009-541563 |
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Nov 2009 |
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JP |
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WO 95/11933 |
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May 1995 |
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WO |
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WO 2008/000831 |
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Jan 2008 |
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WO |
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WO 2009/010522 |
|
Jan 2009 |
|
WO |
|
WO 2010112537 |
|
Oct 2010 |
|
WO |
|
Other References
Office Action/Search Report dated Mar. 20, 2017, by the Chinese
Patent Office in corresponding Chinese Patent Application No.
201480004120.7 and English translation of the Office Action/Search
Report. (21 pages). cited by applicant .
International Search Report (PCT/ISA/210) dated Feb. 25, 2014, by
the European Patent Office as the International Searching Authority
for International Application No. PCT/EP2014/051135. cited by
applicant .
Written Opinion (PCT/ISA/237) dated Feb. 25, 2014, by the European
Patent Office as the International Searching Authority for
International Application No. PCT/EP2014/051135. cited by applicant
.
International Search Report (PCT/ISA/210) dated Mar. 6, 2014, by
the European Patent Office as the International Searching Authority
for International Application No. PCT/EP2014/051137. cited by
applicant .
Written Opinion (PCT/ISA/237) dated Mar. 6, 2014, by the European
Patent Office as the International Searching Authority for
International Application No. PCT/EP2014/051137. cited by applicant
.
Nov. 12, 2018 Office Action issued in European Patent Application
No. 14701064.9. cited by applicant .
Jun. 12, 2018 Office Action issued in Chinese Patent Application
No. 201480004120.7. cited by applicant .
Dec. 11, 2017 Office Action issued in Chinese Patent Application
No. 201480004120.7. cited by applicant .
Jan. 9, 2018 Office Action issued in Japanese Patent Application
No. 2015-553123. cited by applicant.
|
Primary Examiner: Sastri; Satya B
Attorney, Agent or Firm: Oliff PLC
Claims
The invention claimed is:
1. A one-part moisture-curing liquid-applied waterproofing membrane
comprising: at least one isocyanate-functional polyurethane polymer
based on an aliphatic polyisocyanate; at least one aldimine of the
formula (I), ##STR00007## wherein A is an n-valent hydrocarbyl
moiety of molecular weight in the range of 28 to 5000 g/mol
optionally containing ether or urethane groups, R.sup.1 and R.sup.2
are the same or different C.sub.1 to C.sub.12 linear or branched
alkyls, or are joined together to form a divalent linear or
branched C.sub.4 to C.sub.12 hydrocarbyl moiety which is part of a
5- to 8-membered carbocyclic ring, R.sup.3 is hydrogen or a linear
or branched C.sub.1 to C.sub.12 alkyl or arylalkyl or
alkoxycarbonyl, R.sup.4 is a monovalent C.sub.6 to C.sub.20
hydrocarbyl moiety optionally containing ether, carbonyl or ester
groups, and n is from 2 to 6; and at least one oxazolidine of the
formula (II), ##STR00008## wherein B is a m-valent hydrocarbyl
moiety of molecular weight in the range of 28 to 2000 g/mol
optionally containing ether, ester, amide, carbonate, urethane, or
urea groups, R.sup.5 is selected from hydrogen or C.sub.1 to
C.sub.12 linear or branched alkyl, R.sup.6 is a C.sub.3 branched
alkyl, and m is 2 or 3; wherein the ratio between the number of
aldimino groups and the number of oxazolidino groups is in the
range of 80/20 to 20/80.
2. The membrane according to claim 1, wherein the aldimine of the
formula (I) is selected from the group consisting of
N,N'-bis(2,2-dimethyl-3-lauroyloxypropylidene)-hexamethylene-1,6-diamine,
N,N'-bis(2,2-dimethyl-3-lauroyloxypropylidene)-3-aminomethyl-3,5,5-trimet-
-hylcyclohexylamine,
N,N'-bis(2,2-dimethyl-3-lauroyloxypropylidene)-polyoxypropylene
diamine with an average molecular weight in the range of 700 to
4,600 g/mol, and
N,N',N''-tris(2,2-dimethyl-3-lauroyloxypropylidene)-polyoxypropylene
triamine with an average molecular weight in the range of 1,200 to
5,800 g/mol.
3. The membrane according to claim 1 comprising: a combination of
at least two different aldimines of the formula (I).
4. The membrane according to claim 1, wherein R.sup.5 is
hydrogen.
5. The membrane according to claim 1, wherein the formula (II)
corresponds to the formula (II a) or (II b): ##STR00009##
6. The membrane according to claim 1 further comprising: at least
one ingredient selected from the group consisting of inorganic
fillers and pigments, at least one ingredient selected from the
group consisting of flame-retarding plasticizers and
flame-retarding fillers, and at least one ingredient selected from
the group consisting of catalysts, plasticizers, solvents and
UV-stabilizers.
7. The membrane according to claim 1 containing from 15 to 70
weight-% isocyanate-functional polyurethane polymers; from 20 to 80
weight-% of fillers including inorganic fillers, flame-retarding
fillers and pigments; from 5 to 30 weight-% of plasticizers
including flame-retarding plasticizers; and at least one further
ingredient selected from the group consisting of catalysts,
solvents and UV-stabilizers.
8. The membrane according to claim 1 having a Brookfield viscosity
in the range of 2,000 to 15,000 mPas at 20.degree. C.
9. The membrane according to claim 1 containing 50 g VOC per liter
or less.
10. A waterproofing system comprising: optionally a primer and/or
an undercoat, one or more than one layer of the membrane according
to claim 1, and optionally a top coat.
11. A method of waterproofing a roof structure, comprising:
applying the membrane according to claim 1 in liquid state onto a
substrate of the roof structure in a layer thickness in the range
of 0.5 to 3 mm; contacting the membrane with a fibre reinforcement
mesh within the open time of the membrane; exposing the membrane to
moisture to thereby cure the membrane partially or fully to obtain
an elastic coating; and optionally applying a second layer of the
membrane in a layer thickness in the range of 0.5 to 3 mm and
curing the second layer by exposure to moisture.
12. A waterproof roof structure, obtained by the method according
to claim 11.
13. The membrane according to claim 1, wherein R.sup.5 is a C.sub.1
to C.sub.12 linear or branched alkyl.
14. The membrane according to claim 1, wherein m is 3.
15. The membrane according to claim 1, wherein the ratio between
the number of aldimino groups and the number of oxazolidino groups
is in the range of 75/25 to 25/75.
16. The membrane according to claim 1, wherein the ratio between
the number of aldimino groups and the number of oxazolidino groups
is in the range of 70/30 to 30/70.
17. The membrane according to claim 1, wherein the ratio between
the number of aldimino groups and the number of oxazolidino groups
is in the range of 75/25 to 35/65.
18. The membrane according to claim 1, wherein the ratio between
the number of aldimino groups and the number of oxazolidino groups
is in the range of 60/40 to 40/60.
Description
FIELD OF THE INVENTION
The invention relates to a liquid-applied waterproofing membrane
based on one-part moisture-curing polyurethane, particularly for
roofing applications.
BACKGROUND OF THE INVENTION
Liquid-applied waterproofing membranes are known. In roofing
applications they are used as an alternative to prefabricated sheet
membranes, offering easier application especially in the case of
complex roof geometries and for refurbishment tasks, providing a
flexible seamless roof coating which is fully adhered to the
substrate.
Liquid-applied waterproofing membranes on roofs have to fulfill
demanding requirements. They need to have a low viscosity to be
applied as self-levelling coatings and a sufficiently long open
time to enable hand application, but still cure fast in order to
quickly lose their vulnerability. When fully cured the roofing
membrane needs to have durable elasticity and strength in order to
protect the building effectively from water ingress in a broad
temperature range and under outdoor weathering conditions, such as
wind forces, ponding water, frost, strong sunlight irradiation,
microbial attack and root penetration.
State-of-the-art liquid-applied waterproofing membranes are often
reactive polyurethane compositions, formulated as one-part or as
two-part systems, also called single-component or two-component
systems, respectively. Two-part systems are more complex to apply,
requiring special mixing equipment and proper metering of the two
components, since mistakes in mixing quality and/or stoichiometry
strongly affect the membrane performance. One-part systems are easy
to apply, but prone to curing defects. State-of-the-art one-part
systems comprise blocked amine hardeners, in particular
oxazolidines, to prevent excessive gassing from carbon dioxide
formation on curing. They generally contain considerable amounts of
solvents to guarantee low viscosity and sufficient shelf life.
Attempts spurred by tightening VOC regulation to reduce the solvent
content of such one-part systems typically result in difficulties
with shelf life stability and bad workability because of high
viscosity, as the viscosity of the compositions starts on a higher
level and increases further from premature crosslinking reactions
between the NCO groups of the prepolymer and the oxazolidine
hardeners during storage. Further drawbacks of oxazolidine-based
one-part membranes are related to slow curing and unpleasant odours
caused by the emission of the blocking agent, a volatile aldehyde
or ketone.
WO 2008/000831 discloses low VOC coating compositions, preferably
for flooring purposes, which are based on aldol ester polyaldimines
as blocked amine hardeners. While these compositions have good
shelf life stability and cure without generating unpleasant odours,
they are limited in strength development due to the low
functionality hardener and the plasticizing effect of the aldol
ester blocking agent. The coatings of the examples are either too
stiff for roofing applications or contain high amounts of
solvent.
SUMMARY OF THE INVENTION
The task of this invention is to provide a one-part liquid-applied
waterproofing membrane useful for roofing applications having good
shelf life stability and good workability at low solvent content,
even when only about 50 g VOC per liter or less, as well as fast
and reliable curing properties.
Surprisingly it was found that the liquid-applied waterproofing
membrane according to Claim 1 fulfills this task and has additional
benefits. It comprises an isocyanate-functional polyurethane
polymer providing good tensile strength and high elongation almost
independent of temperature, remaining elastic also under cold
climate conditions. It further comprises an aldol ester aldimine in
a specific ratio range with an oxazolidine. This specific
combination surprisingly affords a very attractive set of
properties not reached by state-of-the-art membranes based on
aldimines or oxazolidines alone: good shelf life stability and a
low viscosity even at low solvent content, good mechanical
properties, in particular high tensile strength in conjunction with
high elongation, long open time allowing hand application yet fast
and reliable curing properties preventing defects. The combination
of an aldimine and an oxazolidine as two separate molecules instead
of using one molecule carrying both aldimino and oxazolidino groups
offers the advantage that the aldimine and the oxazolidine are
derived from different types of aldehydes, as oxazolidines derived
from aldol ester aldehydes are not hydrolysing fast enough and
aldimines derived from alkylaldehydes increase smell and aldehyde
emission of the membrane.
The possibility of combining low solvent content with long shelf
life provides the formulator with the unique opportunity to obtain
a high-end product fulfilling toughest VOC regulations, having
minimal shrinkage and a very low odour profile. The fast curing
properties in conjunction with a long open time allow careful
application and provide high early strength, thus minimizing the
time in which the membrane is vulnerable and speeding up
application in case of a multi-layer build-up. The good mechanical
properties afford high crack-bridging qualities in a broad
temperature range and ensure high durability.
Another aspect of the invention is the use of an aldol ester
aldimine as a non-VOC diluent for oxazolidine-based one-part
moisture-curing liquid-applied waterproofing membranes, providing
additional benefits, such as good shelf life stability of the
uncured material, faster curing, less odour and high strength and
elongation of the cured membrane.
The liquid-applied membrane according to Claim 1 is particularly
suitable for use on a roof, particularly on a flat or low slope
roof. It is particularly advantageous for detailing work and for
refurbishment purposes.
Other aspects of the invention are revealed in other independent
claims. Preferred aspects of the invention are revealed in the
dependent claims.
DETAILED DESCRIPTION OF THE INVENTION
The subject of the present invention is a one-part moisture-curing
liquid-applied waterproofing membrane comprising at least one
isocyanate-functional polyurethane polymer; at least one aldimine
of the formula (I),
##STR00001## wherein A is an n-valent hydrocarbyl moiety of
molecular weight in the range of 28 to 5000 g/mol optionally
containing ether or urethane groups, R.sup.1 and R.sup.2 are the
same or different C.sub.1 to C.sub.12 linear or branched alkyls, or
are joined together to form a divalent linear or branched C.sub.4
to C.sub.12 hydrocarbyl moiety which is part of a 5- to 8-membered
carbocyclic ring, R.sup.3 is hydrogen or a linear or branched
C.sub.1 to C.sub.12 alkyl or arylalkyl or alkoxycarbonyl, R.sup.4
is a monovalent C.sub.6 to C.sub.20 hydrocarbyl moiety optionally
containing ether, carbonyl or ester groups, and n is from 2 to 6;
at least one oxazolidine of the formula (II),
##STR00002## wherein B is a m-valent hydrocarbyl moiety of
molecular weight in the range of 28 to 2000 g/mol optionally
containing ether, ester, amide, carbonate, urethane or urea groups,
R.sup.5 and R.sup.6 are independently selected from hydrogen or
C.sub.1 to C.sub.12 linear or branched alkyl, and m is 2 or 3;
whereby the ratio between the number of aldimino groups and the
number of oxazolidino groups is in the range of 80/20 to 20/80.
In this document, the term "one-part moisture-curing" refers to a
liquid-applied membrane, which is contained in a single
moisture-tight container, has a certain shelf life stability and
cures when exposed to moisture.
In this document the term "liquid-applied waterproofing membrane"
refers to a material which is applied in liquid form as a layer
onto a substrate, and which cures to form an elastic membrane
making the substrate waterproof.
In this document, the term "polyurethane polymer" includes all
polymers prepared by the so-called diisocyanate polyaddition
process. It includes isocyanate-functional polyurethane polymers
obtained by reacting polyisocyanates and polyols, which may also be
called prepolymers and are polyisocyanates themselves.
In this document, the term "shelf life stability" refers to the
ability of a composition to be stored at room temperature in a
suitable container under exclusion of moisture for a certain time
interval, in particular several months, without undergoing
significant changes in application or end-use properties.
In this document, substance names starting with "poly", such as
polyol, polyisocyanate or polyamine, refer to substances carrying
two or more of the respective functional groups (e.g. OH groups in
the case of polyol) per molecule.
In this document an amine or an isocyanate is called "aliphatic"
when its amino group or its isocyanate group, respectively, is
directly bound to an aliphatic, cycloaliphatic or arylaliphatic
moiety. The corresponding functional group is therefore called an
aliphatic amino or an aliphatic isocyanate group, respectively.
In this document an amine or an isocyanate is called "aromatic"
when its amino group or its isocyanate group, respectively, is
directly bound to an aromatic moiety. The corresponding functional
group is therefore called an aromatic amino or an aromatic
isocyanate group, respectively.
In this document, the term "primary amino group" refers to an
NH.sub.2-group bound to an organic moiety, and the term "secondary
amino group" refers to a NH-group bound to two organic moieties
which together may be part of a ring.
In this document the acronym "VOC" stands for "volatile organic
compounds", which are organic substances having a vapour pressure
of at least 0.01 kPa at a temperature of 293.14 K.
In this document, the term "solvent" refers to a liquid which is a
VOC, which is able to dissolve isocyanate-functional polyurethane
polymers as described in this document, and which does not carry
any isocyanate-reactive functional groups.
In this document, "room temperature" refers to a temperature of
23.degree. C.
In this document the term "molecular weight" refers to the molar
mass (given in grams per mole) of a molecule or a part of a
molecule, also referred to as "moiety". The term "average molecular
weight" refers to the number-average molecular weight (M.sub.n) of
an oligomeric or polymeric mixture of molecules or moieties.
The liquid-applied membrane of this invention comprises at least
one isocyanate-functional polyurethane polymer.
A suitable isocyanate-functional polyurethane polymer may be
obtained from the reaction of at least one polyisocyanate with at
least one polyol, whereby the isocyanate groups are in
stoichiometric excess over the hydroxyl groups. The polyisocyanate
and the polyol are brought to reaction via known methods,
preferably at temperatures between 50 and 100.degree. C.,
optionally by using a suitable catalyst. Preferably the
polyisocyanate is used in an amount corresponding to an isocyanate
to hydroxyl group ratio in the range of 1.3 to 5, more preferably
1.5 to 3. Preferably the polyurethane polymer has a free NCO group
content in the range of 1 to 10 weight-%, preferably 2 to 8
weight-%. Optionally the polyol and the polyisocyanate may be
reacted in the presence of a plasticizer or a solvent which are
free from isocyanate-reactive groups.
Preferably the isocyanate-functional polyurethane polymer has an
average molecular weight in the range of 1,000 to 10,000 g/mol,
more preferably in the range of 1,000 to 5,000 g/mol.
Preferably the isocyanate-functional polyurethane polymer has an
average isocyanate functionality in the range of 1.7 to 3, more
preferably 1.8 to 2.5.
Suitable polyols for preparing the isocyanate-functional
polyurethane polymer are polyether polyols, including those
containing dispersed styrene-acrylonitrile (SAN),
acrylonitrile-methylmethacrylate or urea particles, further
polyester polyols such as products of the polycondensation reaction
of diols or triols with lactones or dicarboxylic acids or their
esters or anhydrides, further polycarbonate polyols, block
copolymer polyols with at least two different blocks of polyether,
polyester or polycarbonate units, polyacrylate and polymethacrylate
polyols, polyhydroxy-functional fats and oils, especially natural
fats and oils, and polyhydrocarbon polyols, such as
polyhydroxy-functional polyolefins.
Along with the above-mentioned polyols, small amounts of low
molecular weight divalent or multivalent alcohols can be used, such
as 1,2-ethanediol, 1,2-propanediol, neopentyl glycol,
dibromoneopentyl glycol, diethylene glycol, triethylene glycol, the
isomeric dipropylene glycols and tripropylene glycols, the isomeric
butanediols, pentanediols, hexanediols, heptanediols, octanediols,
nonanediols, decanediols, undecanediols, 1,3- and
1,4-cyclohexanedimethanol, hydrogenated bisphenol A, dimer fatty
alcohols, 1,1,1-trimethylolethane, 1,1,1-trimethylolpropane,
glycerol, pentaerythritol, sugar alcohols, such as xylitol,
sorbitol or mannitol, sugars, such as saccharose, other polyhydric
alcohols, low molecular weight alkoxylation products of the
above-mentioned divalent or multivalent alcohols, as well as
mixtures of the above-mentioned alcohols.
Preferred polyols are diols and triols with an average molecular
weight in the range of 500 to 6,000 g/mol, particularly in the
range of 1,000 to 5,000 g/mol.
Preferred polyols are polyether polyols, polyester polyols,
polycarbonate polyols and polyacrylate polyols.
Particularly preferred polyols are polyether polyols, particularly
polyoxyalkylenepolyols. These polyols help to develop good low
temperature flexibility in the cured membrane.
Polyoxyalkylenepolyols are products of the polymerziation of
ethylene oxide, 1,2-propylene oxide, 1,2- or 2,3-butylene oxide,
oxetane, tetrahydrofuran or mixtures thereof, optionally
polymerized using a starter molecule with two or more active
hydrogen atoms, such as water, ammonia or compounds with several
OH- or NH-groups, such as 1,2-ethanediol, 1,2- and 1,3-propanediol,
neopentylglycol, diethyleneglycol, triethyleneglycol, the isomeric
dipropyleneglycols and tripropyleneglycols, the isomeric
butanediols, pentanediols, hexanediols, heptanediols, octanediols,
nonanediols, decanediols, undecanediols, 1,3- and
1,4-cyclohexanedimethanol, bisphenol A, hydrogenated bisphenol A,
1,1,1-trimethylolethane, 1,1,1-trimethylolpropane, glycerol,
aniline, as well as mixtures of the above-mentioned compounds.
Preferred are both polyoxyalkylenepolyols with a low degree of
unsaturation (measured according to ASTM D-2849-69 and indicated in
milliequivalents of unsaturation per gram of polyol (meq/g)),
obtainable, for example, by using so-called double metal cyanide
complex catalysts (DMC catalysts), and polyoxyalkylenepolyols with
a higher degree of unsaturation, obtainable, for example, by using
anionic catalysts such as NaOH, KOH, CsOH or alkali alcoholates.
Particularly preferred polyoxyalkylenepolyols are polymerization
products of ethylene oxide and/or propylene oxide.
More preferred are polyoxypropylenepolyols and so-called ethylene
oxide endcapped polyoxypropylenepolyols. The latter are specific
polyoxypropylene-polyoxyethylenepolyols obtainable by
post-ethoxylating pure polyoxypropylenepolyols, thus featuring
primary hydroxyl groups. These polyols enable good low temperature
flexibility and good weathering properties in the cured
membrane.
Particularly preferred polyoxyalkylenepolyols are
polyoxypropylenediols and -triols and ethylene oxide endcapped
polyoxypropylenediols and -triols with an average molecular weight
in the range of 500 to 6,000 g/mol, particularly in the range of
1,000 to 4,000 g/mol.
These polyether polyols provide a combination of low viscosity,
good weathering properties and good mechanical properties in the
cured membrane.
Further particularly preferred polyols are polycarbonate polyols,
particularly products of the polycondensation of dialkyl
carbonates, diaryl carbonates or phosgene with diols or triols such
as ethylene glycol, diethylene glycol, propylene glycol,
dipropylene glycol, neopentyl glycol, 1,4-butanediol,
1,5-pentanediol, 3-methyl-1,5-hexanediol, 1,6-hexanediol,
1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol,
1,12-octadecanediol, 1,4-cyclohexane dimethanol, dimeric fatty acid
diol (dimeryl diol), hydroxypivalic neopentylglycol ester, glycerol
and 1,1,1-trimethylolpropane.
Such polycarbonate polyols can help to develop good weathering
properties of the membrane.
Preferred low molecular weight alcohols are difunctional alcohols
with a molecular weight in the range of 60 to 150 g/mol.
Particularly preferred are 1,2-ethanediol, 1,3-propanediol,
1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,3-cyclohexane
dimethanol, 1,4-cyclohexane dimethanol and diethylene glycol. These
alcohols improve particularly the strength of the membrane. Most
preferred is 1,4-butanediol.
Further preferred low molecular weight alcohols are difunctional
bromated alcohols such as dibromoneopentyl glycol. These alcohols
improve particularly the flame retarding properties of the
membrane.
Preferably the isocyanate-functional polyurethane polymer is
prepared from a polyol mixture comprising at least 50 weight-%,
more preferably at least 80 weight-%, and most preferably at least
90 weight-%, of polyether polyols.
In a particularly preferred embodiment, the isocyanate-functional
polyurethane polymer is obtained from a combination of at least one
polyether polyol with a molecular weight in the range of 500 to
6,000 g/mol and at least one diol with a molecular weight in the
range of 60 to 150 g/mol, particularly 1,4-butanediol. Such an
isocyanate-functional polyurethane polymer shows a low viscosity
and provides good mechanical properties, particularly high
strength.
Suitable polyisocyanates to obtain the isocyanate-functional
polyurethane polymer are the following: Aliphatic polyisocyanates,
particularly 1,4-tetramethylene diisocyanate,
2-methylpentamethylene-1,5-diisocyanate, 1,6-hexanediisocyanate
(HDI), 2,2,4- and 2,4,4-trimethyl-1,6-hexanediisocyanate (TMDI),
1,10-decanediisocyanate, 1,12-dodecanediisocyanate, lysine or
lysine ester diisocyanate, cyclohexane-1,3- and -1,4-diisocyanate,
1-methyl-2,4- and -2,6-diisocyanatocyclohexane and any mixtures of
these isomers (HTDI or H.sub.6TDI),
1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane
(isophoronediisocyanate or IPDI), perhydro-2,4'- and
-4,4'-diphenylmethane diisocyanate (HMDI or H.sub.12MDI),
1,4-diisocyanato-2,2,6-trimethylcyclohexane (TMCDI), 1,3- and
1,4-bis-(isocyanatomethyl)cyclohexane, m- and p-xylylene
diisocyanate (m- and p-XDI), m- and p-tetramethyl-1,3- and
-1,4-xylylene diisocyanate (m- and p-TMXDI),
bis-(1-isocyanato-1-methylethyl)naphthalene, dimer or trimer fatty
acid isocyanates, such as
3,6-bis-(9-isocyanatononyl)-4,5-di-(1-heptenyl)cyclohexene (dimeryl
diisocyanate), and
.alpha.,.alpha.,.alpha.',.alpha.',.alpha.'',.alpha.''-hexamethyl-1,3,5-me-
sitylene triisocyanate. Preferred thereof are HDI, TMDI, IPDI and
H.sub.12MDI. Aromatic polyisocyanates, particularly
4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane
diisocyanate and 2,2'-diphenylmethane diisocyanate and any mixtures
of these isomers (MDI), 2,4- and 2,6-toluylene diisocyanate and any
mixtures of these isomers (TDI), 1,3- and 1,4-phenylene
diisocyanate, 2,3,5,6-tetramethyl-1,4-diisocyanatobenzene,
naphthalene-1,5-diisocyanate (NDI),
3,3'-dimethyl-4,4'-diisocyanatodiphenyl (TODI), dianisidine
diisocyanate (DADI), 1,3,5-tris-(isocyanatomethyl)benzene,
tris-(4-isocyanatophenyl)methane and
tris-(4-isocyanatophenyl)thiophosphate. Preferred thereof are MDI
and TDI.
Preferred polyisocyanates to obtain the isocyanate-functional
polyurethane polymer are aliphatic polyisocyanates. Such polymers
provide liquid-applied membranes with a particularly good shelf
life stability and light-fastness, i.e. yellowing resistance under
sunlight exposure, as well as good UV-resistance. The most
preferred aliphatic polyisocyanate to obtain the
isocyanate-functional polyurethane polymer is IPDI. Such polymers
provide particularly low viscous liquid-applied membranes having
high strength and high elongation.
In one embodiment of the invention, preferred polyisocyanates to
obtain the isocyanate-functional polyurethane polymer are aromatic
polyisocyanates, in particular MDI. MDI is preferred from an EHS
point of view since it has a very low volatility. Moreover MDI is
inexpensive and affords fast curing and high strength
membranes.
To obtain the isocyanate-functional polyurethane polymer, it can be
advantageous to use polyisocyanates containing a certain amount of
their oligomers or polymers or other derivatives. Especially in the
case of MDI, it can be advantageous to use mixtures of MDI with
oligomers or polymers or derivatives of MDI, preferably so-called
modified MDI containing carbodiimides or uretonimines or urethanes
of MDI, which are commercially available e.g. as Desmodur.RTM.CD,
Desmodur.RTM. PF, Desmodur.RTM. PC (all from Bayer) or Isonate.RTM.
M 143 (from Dow), as well as so-called polymeric MDI or PMDI
representing mixtures of MDI with homologues of MDI, such as
Desmodur.RTM. VL, Desmodur.RTM. VL50, Desmodur.RTM. VL R10,
Desmodur.RTM. VL R20, Desmodur.RTM. VH 20 N and Desmodur.RTM. VKS
20F (all from Bayer), Isonate.RTM. M 309, Voranate.RTM. M 229 and
Voranate.RTM. M 580 (all from Dow) or Lupranate.RTM. M 10 R (from
BASF).
The one-part moisture-curing liquid-applied waterproofing membrane
further comprises at least one aldimine of the formula (I).
##STR00003##
Preferably n is 2 or 3. These aldimines are derived from di- or
triamines and enable membranes having good mechanical properties,
particularly a good combination of high elongation and high
strength.
Preferably R.sup.1 and R.sup.2 are each methyl. These aldimines
enable membranes having low viscosity as well as fast, reliable
curing properties.
Preferably R.sup.3 is hydrogen. These aldimines provide membranes
having low viscosity as well as fast, reliable curing
properties.
Preferably R.sup.4 is C.sub.11 alkyl. These aldimines provide
odourless membranes having low viscosity and high flexibility at
low temperatures.
Particularly preferred are aldimines of the formula (I) wherein
R.sup.1 and R.sup.2 are methyl, R.sup.3 is hydrogen and R.sup.4 is
undecyl. These aldimines provide odourless membranes having low
viscosity, fast and reliable curing properties and high flexibility
at low temperatures.
Preferably A is an n-valent hydrocarbyl moiety of molecular weight
in the range of 28 to 2,000 g/mol, particularly in the range of 84
to 600 g/mol, optionally containing ether groups. Such aldimines
provide membranes having good mechanical properties, particularly
high flexibility at low temperatures and high strength in warm
conditions.
Preferably A is the moiety remaining when removing the primary
amino groups of a polyamine selected from the group consisting of
hexamethylene-1,6-diamine, 2-methylpentane-1,5-diamine,
3-aminomethyl-3,5,5-trimethylcyclohexylamine(isophoronediamine),
2,2,4- and 2,4,4-trimethylhexamethylenediamine,
1,3-bis(aminomethyl)benzene, 1,3-bis(aminomethyl)cyclohexane,
1,4-bis(aminomethyl)cyclohexane, bis(4-aminocyclohexyl)methane,
bis(4-amino-3-methylcyclohexyl)methane,
2,5(2,6)-bis-(aminomethyl)bicyclo[2.2.1]heptane,
3(4),8(9)-bis(aminomethyl)-tricyclo[5.2.1.0.sup.2,6]decane,
1,2-diaminocyclohexane, 1,3-diaminocyclohexane,
1,4-diaminocyclohexane, 2,2,6-trimethylcyclohexane-1,4-diamine,
3,6-dioxaoctane-1,8-diamine, 4,7-dioxadecane-1,10-diamine,
4-aminomethyl-1,8-octanediamine, polyoxypropylene diamines and
triamines with an average molecular weight in the range of 200 to
5,000 g/mol, preferably 200 to 2000 g/mol, more preferably 200 to
600 g/mol, 1,3-phenylene diamine, 1,4-phenylene diamine, 2,4- and
2,6-toluylene diamine and 4,4'-, 2,4'- and
2,2'-diaminodiphenylmethane.
In a particularly preferred embodiment of the invention A is the
moiety remaining when removing the primary amino groups of
hexamethylene-1,6-diamine. These aldimines provide membranes having
particularly low viscosity and fast curing properties.
In another particularly preferred embodiment of the invention, A is
the moiety remaining when removing the primary amino groups of
isophoronediamine. These aldimines provide membranes having
particularly low viscosity and high strength.
In another particularly preferred embodiment of the invention, A is
the moiety remaining when removing the primary amino groups of a
polyoxypropylene diamine or triamine with an average molecular
weight in the range of 200 to 5,000 g/mol, preferably 200 to 2000
g/mol, more preferably 200 to 600 g/mol. These aldimines provide
membranes having particularly low viscosity, fast curing properties
and high elongation.
In a most preferred embodiment of the invention, A is the moiety
remaining when removing the primary amino groups of a
polyoxypropylene triamine with an average molecular weight in the
range of 400 to 5,000 g/mol, preferably 400 to 500 g/mol,
particularly Jeffamine.RTM. T-403 from Huntsman or a corresponding
grade from BASF or Nitroil, or Jeffamine.RTM. T-5000 from Huntsman
or a corresponding grade from BASF or Nitroil. These aldimines
provide membranes with very fast curing properties and a good
combination of high elongation and strength.
Preferred aldimines of the formula (I) are selected from the group
consisting of
N,N'-bis(2,2-dimethyl-3-lauroyloxypropylidene)-hexamethylene-1,6-diamine,
N,N'-bis(2,2-dimethyl-3-lauroyloxypropylidene)-3-aminomethyl-3,5,5-trimet-
hylcyclohexylamine,
N,N'-bis(2,2-dimethyl-3-lauroyloxypropylidene)-polyoxypropylene
diamine with an average molecular weight in the range of 700 to
4,600 g/mol and
N,N',N''-tris(2,2-dimethyl-3-lauroyloxypropylidene)-polyoxypropylene
triamine with an average molecular weight in the range of 1,200 to
5,800 g/mol.
These aldimines provide odourless membranes with good workability
and fast curing properties, as well as high elongation and good
strength when cured.
In a particularly preferred embodiment of the invention the
aldimine of the formula (I) is
N,N'-bis(2,2-dimethyl-3-lauroyloxypropylidene)-hexamethylene-1,6-diamine.
This aldimine provides odourless membranes with a particularly low
viscosity and fast curing properties.
In another particularly preferred embodiment of the invention the
aldimine of the formula (I) is
N,N'-bis(2,2-dimethyl-3-lauroyloxypropylidene)-3-aminomethyl-3,5,5-trimet-
hylcyclohexylamine. This aldimine provides odourless membranes with
particularly low viscosity and high strength.
In another particularly preferred embodiment of the invention the
aldimine of the formula (I) is
N,N'-bis(2,2-dimethyl-3-lauroyloxypropylidene)-polyoxypropylene
diamine or
N,N',N''-tris(2,2-dimethyl-3-lauroyloxypropylidene)-polyoxypropylene
triamine. These aldimines provide membranes having particularly low
viscosity, fast curing properties and high elongation. Especially
preferred are the trialdimines. They provide very fast curing
properties and a good combination of high strength and high
elongation.
In a particularly preferred embodiment of the invention, the
liquid-applied membrane comprises a combination of at least two
different aldimines of the formula (I). The use of more than one
aldimine of the formula (I) gives the possibility to balance
properties such as viscosity, cure speed, tensile strength and
elongation in an optimal way.
Preferably, one of the two different aldimines of the formula (I)
is a dialdimine and the other one is a trialdimine.
The trialdimine is preferably
N,N',N''-tris(2,2-dimethyl-3-lauroyloxypropylidene)polyoxypropylene
triamine with an average molecular weight in the range of 1,200 to
5,800 g/mol, preferably 1,200 to 1,300 g/mol.
The dialdimine is preferably selected from the group consisting of
N,N'-bis(2,2-dimethyl-3-lauroyloxypropylidene)-hexamethylene-1,6-diamine
and
N,N'-bis(2,2-dimethyl-3-lauroyloxypropylidene)-3-aminomethyl-3,5,5-tr-
imethylcyclohexylamine.
Such membranes show an unexpectedly good combination between low
viscosity, fast curing properties, high strength and high
elongation.
Aldimines of the formula (I) are preferably available from a
condensation reaction of at least one amine of the formula (III)
and at least one aldehyde of the formula (IV).
##STR00004##
In the formula (III) and (IV), A, n, R.sup.1, R.sup.2, R.sup.3 and
R.sup.4 have the already mentioned meanings.
For this condensation reaction, the aldehyde of the formula (IV) is
used stochiometrically or in excess related to the primary amino
groups of the amine of the formula (III). The reaction can
advantageously be conducted at a temperature in the range between
15 and 120.degree. C., either in the presence of a solvent or
without a solvent. The released water is being removed either
azeotropically with a suitable solvent, or directly under
vacuum.
The one-part moisture-curing liquid-applied waterproofing membrane
further comprises at least one oxazolidine of the formula (II).
##STR00005##
Preferably B is an m-valent hydrocarbyl moiety of molecular weight
in the range of 118 to 500 g/mol containing carbonate or urethane
groups.
Preferably R.sup.5 is hydrogen.
Preferably R.sup.6 is a C.sub.3 to C.sub.7 branched alkyl.
Particularly preferred are 2-propyl and 3-heptyl.
Preferably m is 2.
Such oxazolidines provide membranes with high elongation and high
strength. Particularly preferred are oxazolidines of the formula
(II) wherein R.sup.5 is hydrogen and R.sup.6 is 2-propyl or
3-heptyl.
Particularly preferred are oxazolidines wherein the formula (II)
corresponds to the formula (II a) or (II b).
##STR00006##
In the formula (II a) and (II b) R.sup.5 and R.sup.6 have the
already mentioned meanings.
The oxazolidines of the formula (II a) and (II b) are derivatives
of N-(2-hydroxyethyl)-tetrahydrooxazoles, the latter being
obtainable via the condensation reaction of diethanolamine with
aldehydes or ketones, particularly with isobutyraldehyde or
2-ethylhexanal.
The oxazolidines of the formula (II a) are obtainable by the
reaction of an N-(2-hydroxyethyl)-tetrahydrooxazole with an organic
carbonate.
The oxazolidines of the formula (II b) are obtainable by the
reaction of an N-(2-hydroxyethyl)-tetrahydrooxazole with
1,6-hexanediisocyanate (HDI).
These oxazolidines enable membranes with good workability, good
elongation and high strength.
Examples for commercially available oxazolidines of the formula
(II) are Hardener OZ (from Bayer), Zoldine.RTM. RD-4 (from Angus
Chemical), as well as Incozol.RTM. LV, Incozol.RTM. 4, Incozol.RTM.
HP, Incozol.RTM. NC, Incozol.RTM. CF, Incozol.RTM. EH and
Incozol.RTM. K (from Incorez).
In the liquid-applied membrane, the ratio between the number of
aldimino groups and the number of oxazolidino groups is in the
range of 80/20 to 20/80.
In this range, the membrane features good shelf life stability,
fast and reliable curing properties and good mechanical
properties.
If the aldimino/oxazolidino ratio is above 80/20, the membrane is
too soft and has a low tensile strength.
If the aldimino/oxazolidino ratio is below 20/80, the membrane has
a low shelf life stability, insufficient curing properties, in
particular long skinning time, and is limited in elongation.
Preferably the aldimino/oxazolidino ratio is in the range of 75/25
to 25/75. In this range, the membrane is fast curing, has a very
good shelf life stability, also at low solvent content, and a good
combination of high strength and high elongation.
More preferably, the aldimino/oxazolidino ratio is in the range of
70/30 to 30/70.
In this range, the membrane is fast curing, has a very good shelf
life stability, and particularly high strength and elongation.
Preferably the contents of aldimine and oxazolidine in the
liquid-applied membrane is such that the ratio between the total
number of blocked amino and hydroxyl groups to the number of
isocyanate groups is in the range of 0.3 to 1.0, preferably in the
range of 0.4 to 1.0, more preferably in the range of 0.6 to
1.0.
In this range, the membrane cures without the formation of bubbles
or blisters, resulting in a high strength material.
Preferably the content of the isocyanate-functional polyurethane
polymer in the liquid-applied membrane is in the range of 15 to 70
weight-%, more preferably 15 to 60 weight-%, particularly 15 to 50
weight-%.
Besides the ingredients already mentioned, the membrane may
comprise further ingredients.
Preferably the liquid-applied membrane comprises at least one
filler. Fillers help to develop strength and durability.
Preferred fillers are inorganic fillers, particularly calcium
carbonate ("chalk"), such as ground calcium carbonate (GCC) and
precipitated calcium carbonate (PCC), barium sulfate (barytes),
slate, silicates (quartz), magnesiosilicates (talc), alumosilicates
(clay, kaolin), dolomite, mica, glass bubbles and silicic acid, in
particular highly dispersed silicic acids from pyrolytic processes
(fumed silica). These fillers may or may not carry a surface
coating, e.g. a stearate or siloxane coating.
Further preferred fillers are organic fillers, particularly carbon
black and microspheres.
Preferably the liquid-applied membrane further comprises at least
one pigment. The pigment defines the colour of the membrane, helps
to develop strength and increases durability, particularly
UV-stability.
Preferred pigments are titanium dioxide, iron oxides and carbon
black.
Preferably the liquid-applied membrane further comprises at least
one flame-retarding filler. Preferred flame-retarding fillers are
aluminum trihydroxide (ATH), magnesium dihydroxide, antimony
trioxide, antimony pentoxide, boric acid, zinc borate, zinc
phosphate, melamine borate, melamine cyanurate, ethylenediamine
phosphate, ammonium polyphosphate, di-melamine orthophosphate,
di-melamine pyrophosphate, hexabromocyclododecane,
decabromodiphenyl oxide and tris(bromoneopentyl)phosphate.
Preferably the liquid-applied membrane further comprises at least
one flame-retarding plasticizer, particularly a phosphate or a
phosphonate, particularly triphenyl phosphate (TPP),
diphenyl-tert.butylphenyl phosphate, diphenylcresyl phosphate
(DPK), tricresyl phosphate (TKP), triethyl phosphate,
tris(2-ethylhexyl)phosphate, diphenyl-2-ethylhexyl phosphate (DPO),
tris(2-ethylhexyl)phosphate (TOF), diphenylisodecyl phosphate,
dimethyl propane phosphonate (DMPP), tetraphenyl resorcinol
diphosphate, resorcinol diphosphate oligomer (RDP), ethylenediamine
diphosphate, as well as chloroalkyl phosphate esters such as
tris(1-chloro-2-propyl)phosphate,
tris(1,3-dichloro-2-propyl)phosphate and
2,2-bis(chloromethyl)trimethylene
bis(bis(2-chloroethyl)phosphate).
Preferably the liquid-applied membrane further comprises at least
one polyisocyanate crosslinker with an NCO-functionality of greater
than two, particularly oligomers, polymers or derivatives of the
already mentioned diisocyanates. Preferred aliphatic polyisocyanate
crosslinkers are HDI-biurets, such as Desmodur.RTM. N 100 and N
3200 (from Bayer), Tolonate.RTM. HDB and HDB-LV (from Rhodia) and
Duranate.RTM. 24A-100 (from Asahi Kasei); HDI-isocyanurates, such
as Desmodur.RTM. N 3300, N 3600 and N 3790 BA (from Bayer),
Tolonate.RTM. HDT, HDT-LV and HDT-LV2 (from Rhodia), Duranate.RTM.
TPA-100 and THA-100 (from Asahi Kasei) and Coronate.RTM. HX (from
Nippon Polyurethane); HDI-uretdiones, such as Desmodur.RTM. N 3400
(from Bayer); HDI-iminooxadiazinediones, such as Desmodur.RTM. 3900
(from Bayer); HDI-allophanates, such as Desmodur.RTM. VP LS 2102
(from Bayer) and Basonat.RTM. HA 100, Basonat.RTM. HA 200 and
Basonat.RTM. HA 300 (all from BASF); IPDI-isocyanurates, such as
Desmodur.RTM. Z 4470 (from Bayer) and Vestanat.RTM. T1890/100 (from
Evonik); mixed isocyanurates based on IPDI/HDI, such as
Desmodur.RTM. NZ 1 (from Bayer). Preferred aromatic polyisocyanate
crosslinkers are TDI-oligomers, such as Desmodur.RTM. IL (from
Bayer); modified MDI containing carbodiimides or uretonimines of
MDI, such as the already mentioned ones. Mixed aromatic/aliphatic
polyisocyanate crosslinkers may also be used, in particular
isocyanurates based on TDI/HDI, such as Desmodur.RTM. HL (from
Bayer).
Aliphatic polyisocyanate crosslinkers are particularly preferred in
membranes containing isocyanate-functional polyurethane polymers
based on aliphatic polyisocyanates.
Particularly preferred are IPDI-isocyanurates and mixed
isocyanurates containing IPDI.
Preferably the liquid-applied membrane further comprises at least
one metal-based catalyst accelerating the reaction of the
isocyanate groups. Preferred metal-based catalysts are dialkyltin
complexes, particularly dimethyltin, dibutyltin or dioctyltin
carboxylates, mercaptides or acetoacetonates, such as DMTDL, DBTDL,
DBT(acac).sub.2, DOTDL, dioctyltin(IV)neodecanoate or
DOT(acac).sub.2, bismuth(III) complexes, such as
bismuth(III)octoate or bismuth(III)neodecanoate, zinc(II)
complexes, such as zinc(II)octoate or zinc(II)neodecanoate, and
zirconium(IV) complexes, such as zirconium(IV)octoate or
zirconium(IV)neodecanoate.
Preferably the liquid-applied membrane further comprises at least
one acid catalyst accelerating the hydrolysis of the aldimino and
oxazolidino groups. Preferred acid catalysts are carboxylic acids
and sulfonic acids, particularly aromatic carboxylic acids, such as
benzoic acid or salicylic acid.
Preferably the liquid-applied membrane further comprises at least
one UV-stabilizer. Preferred UV-stabilizers are UV-absorbers, such
as benzophenones, benzotriazoles, oxalanilides, phenyltriazines and
particularly 2-cyano-3,3-diphenylacrylic acid ethyl ester, and
hindered amine light stabilizers (HALS), such as
bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate and other compounds
containing at least one 1,2,2,6,6-pentamethyl-4-piperidinyl moiety.
UV-stabilizers help to prevent the polymer from degradation under
light exposure.
The liquid-applied membrane may further comprise the following
ingredients: other polyisocyanates, such as other
isocyanate-functional polyurethane polymers, particularly those
based on MDI, TDI, IPDI or HDI; blocked amine hardeners other than
aldimines of the formula (I) and oxazolidines of the formula (II),
particularly other aldimines; plasticizers other than phosphates
and phosphonates, particularly phthalates, trimellitates,
succinates, glutarates, adipates, sebacates, azelates, citrates,
benzoates, acetylated glycerin or monoglycerides, hydrogenated
phthalates, fatty acid esters, arylsulfonates or hydrocarbon
resins; organic solvents, such as hydrocarbons, esters or ethers,
particularly acetyl acetone, mesityloxide, cyclohexanone,
methylcyclohexanone, ethyl acetate, propyl acetate,
1-methoxy-2-propylacetate, butyl acetate, diethyl malonate,
diisopropylether, diethylether, dibutylether, ethylene glycol
diethylether, diethylene glycol diethylether, toluene, xylenes,
heptanes, octanes, diisopropylnaphthalenes and petroleum fractions,
such as naphtha, white spirits and petroleum ethers, such as
Solvesso.TM. solvents (from Exxon), hydrogenated aromatic solvents
such as hydrogenated naphtha, methylene chloride, propylene
carbonate, butyrolactone, N-methyl-pyrrolidone and
N-ethyl-pyrrolidone; additives, such as wetting agents, flow
enhancers, levelling agents, defoamers, deaerating agents, drying
agents, antioxidants, adhesion promoters, rheology modifiers,
particularly fumed silica, and biocides.
When using such further ingredients it is advantageous to ensure
that they do not strongly impair the shelf life stability of the
uncured membrane, i.e., do not massively trigger reactions leading
to crosslinking of the polymer during storage. In particular these
further ingredients should not contain any water above trace
quantities. It can be advantageous to dry ingredients physically or
chemically before use.
Preferably the liquid-applied membrane comprises at least one
ingredient selected from the group consisting of inorganic fillers
and pigments, at least one ingredient selected from the group
consisting of flame-retarding plasticizers and flame-retarding
fillers, and at least one ingredient selected from the group
consisting of catalysts, plasticizers, solvents and
UV-stabilizers.
These further ingredients provide membranes with good shelf life
stability, good workability, fast curing properties as well as high
strength and durability, which have a low tendency to develop
flames and smoke in case of fire. Such membranes are highly
suitable for applications on a roof.
Preferably the liquid-applied membrane has a filler content in the
range of 20 to 80 weight-%, more preferably in the range of 30 to
60 weight-%, the filler including inorganic, organic and
flame-retarding fillers and pigments. At this filler content the
membrane provides high strength and durability.
A particularly preferred membrane contains from 15 to 70 weight-%
isocyanate-functional polyurethane polymers; from 20 to 80 weight-%
fillers including inorganic fillers, flame-retarding fillers and
pigments; from 5 to 30 weight-%, preferably from 5 to 20 weight-%,
plasticizers including flame-retarding plasticizers; and comprises
at least one further ingredient selected from the group consisting
of catalysts, solvents and UV-stabilizers.
Preferably, it comprises at least one flame-retarding ingredient
selected from the group consisting of flame-retarding fillers and
flame-retarding plasticizers. Such a membrane has good shelf life
stability, good workability at low solvent content, good mechanical
properties and durability and a low tendency to develop flames and
smoke in case of fire.
Preferably the liquid-applied membrane has a low viscosity. This
enables a good workability when applied as a self-levelling
coating. Particularly the membrane has a Brookfield viscosity in
the range of 2,000 to 15,000 mPas at 20.degree. C., preferably in
the range of 2,000 to 10,000 mPas at 20.degree. C. In this
viscosity range the membrane is self-levelling enough to allow easy
application on flat or low slope roof surfaces but does not flow
away into small cavities on the substrate surface.
Preferably the liquid-applied membrane has a low solvent content;
most preferably it contains 50 g VOC per liter or less. At such low
solvent content the membrane fulfills toughest VOC specifications,
e.g. those of the South Coast Air Quality Management District.
State-of-the-art one-part moisture-curing liquid-applied
waterproofing membranes based on isocyanate-functional polyurethane
polymers and blocked amine hardeners are difficult to formulate at
low solvent content. Especially low viscosity and sufficient shelf
life stability is difficult to achieve without the use of high
amounts of solvents. In this invention it was surprisingly found
that the use of an aldimine of the formula (I) in one-part
moisture-curing liquid-applied waterproofing membranes comprising
an isocyanate-functional polyurethane polymer and an oxazolidine is
an effective method to reduce the viscosity and enhance shelf life
stability, thus allowing to decrease solvent contents and providing
the opportunity to formulate high-end yet low VOC and low odour
waterproofing membranes. In addition, it was surprisingly found
that the use of an aldimine of the formula (I) in an
oxazolidine-based membrane is an effective method to significantly
accelerate curing.
A further subject of the invention is the use of at least one
aldimine of the formula (I) as a diluent in a one-part
moisture-curing liquid-applied waterproofing membrane comprising at
least one isocyanate-functional polyurethane polymer and at least
one oxazolidine of the formula (II).
Preferably the aldimine of the formula (I) is used in an amount
corresponding to an aldimino to oxazolidino group ratio in the
range of 80/20 to 20/80, preferably in the range of 75/25 to 35/65,
more preferably in the range of 60/40 to 40/60. This use provides
membranes having a low viscosity at low solvent content, good shelf
life stability, fast curing properties, as well as high elongation
and high strength after curing.
The one-part moisture-curing liquid-applied waterproofing membrane
may be prepared by mixing all ingredients under exclusion of
moisture to obtain a homogeneous fluid. It may be stored in a
suitable moisture-tight container, particularly a bucket, a drum, a
hobbock, a bag, a sausage, a cartridge, a can or a bottle.
The membrane is applied in liquid state within its open time,
typically by pouring it onto the substrate, followed by spreading
it, e.g. with a roller or a squeegee, to get the desired layer
thickness, which is typically in the range of 0.5 to 3 mm,
particularly 0.75 to 1.5 mm.
"Open time" means hereby the period of time between the exposure to
moisture and the formation of a skin on the surface of the
membrane, also called "tack-free time" or "skinning time".
The membrane is self-levelling, which means its viscosity is low
enough to develop an even surface after being spread by rolling or
brushing.
The curing of the membrane starts when it gets in contact with
moisture, typically atmospheric moisture. The curing process works
by chemical reaction. Both aldimino and oxazolidino groups are
activated with moisture and then react with isocyanate groups. On
activation, each aldimino group forms a primary amino group, while
each oxazolidino group forms a secondary amino group and a hydroxyl
group. Furthermore, the isocyanate groups can also react directly
with moisture. As a result of these reactions, the membrane cures
to a solid, elastic material. The curing process may also be called
crosslinking. After curing, an elastic material with a very good
adhesion to a large number of substrates is obtained.
In the course of the curing reaction, the blocking agents of the
aldimines and oxazolidines present in the membrane are released. In
the case of an aldimine of the formula (I), the blocking agent is
an aldehyde of the formula (IV); in the case of an oxazolidine of
formula (II), it is an aliphatic aldehyde or ketone, preferably an
aldehyde. These blocking agents, depending on their volatility and
other factors such as their solubility in the membrane, may
evaporate from the membrane during or after curing, or may remain
in the cured membrane. The latter is particularly the case for
aldehydes of the formula (IV), which are of low volatility and have
little odour or are odourless. This reduces odour, emission and
shrinkage of the membrane. The preferred aldimines of the formula
(I) release 2,2-dimethyl-3-lauroyloxypropanal, which is completely
odourless and remains almost completely in the cured membrane,
being compatible with the crosslinked polyurethane polymer and
acting as a plasticizer.
The membrane can be applied onto various substrates, forming an
elastic coating on the substrate. It can be used particularly for
waterproofing a roof, a roof deck or a roof garden, as well as a
planter, a balcony, a terrace, a plaza, or a foundation. It can
also be used indoors for waterproofing, particularly under ceramic
tiles, e.g. in a bath room, a catering kitchen or a plant room,
protecting them from water ingress. The membrane is particularly
suitable for refurbishment purposes.
Most preferred is the use of the liquid-applied membrane on a roof,
particularly a flat or low slope roof. It can be used to waterproof
a new roof as well as for refurbishment purposes and is
particularly useful for detailing work.
The liquid-applied membrane is preferably used as part of a
waterproofing system, consisting of optionally a primer and/or an
undercoat, one or more than one layers of the membrane, preferably
in combination with a fibre reinforcement mesh, and optionally a
top coat.
The membrane is preferably used by being poured onto a substrate,
being spread evenly within its open time to the desired layer
thickness, typically in the range of 0.5 to 3 mm, particularly in
the range of 0.75 to 1.5 mm, by a roller, a brush, a spreading
knife or a wiper.
Preferably the fibre reinforcement mesh is applied after the first
layer of the membrane, by placing it on top of the freshly applied
membrane and then rolling or working it thoroughly into the
membrane within the open time of the membrane, particularly by
means of a roller or a brush. The membrane with the incorporated
fibre reinforcement mesh is then cured at least to the point that
it can be walked on, before an optional next layer of the membrane
is applied.
It can be advantageous to apply a top coat onto the top layer of
the membrane, such as a covering lacquer or the like. Especially
for liquid-applied membranes based on aromatic isocyanates, it is
advantageous to apply an UV-resistant top coat onto the cured
membrane.
Another subject of the invention is a method of waterproofing a
roof structure, comprising applying the membrane in liquid state
onto a substrate of the roof structure in a layer thickness in the
range of 0.5 to 3 mm, particularly in the range of 0.75 to 1.5 mm;
contacting the membrane with a fibre reinforcement mesh within the
open time of the membrane; exposing the membrane to moisture to
thereby cure the membrane partially or fully to obtain an elastic
coating; optionally applying a second layer of the membrane in a
layer thickness in the range of 0.5 to 3 mm, particularly in the
range of 0.75 to 1.5 mm, and curing it by exposure to moisture.
The fibre reinforcement mesh is preferably a non-woven polyester
fibre mesh and more preferably a non-woven glass fibre mesh.
The fibre reinforcement mesh acts as a reinforcement for the
membrane, providing increased strength and durability. The randomly
orientated fibres in the preferred non-woven fibre meshes give a
multidirectional strength to the membrane while allowing it to
remain highly elastic. It improves strength, tear resistance and
puncture resistance. The non-woven glass fibre mesh shows a
particularly easy handling, as it is not stiff, but easily adapts
to the given surface topography.
Substrates onto which the membrane can be applied are particularly
concrete, lightweight concrete, mortar, brick, adobe, tile, slate,
gypsum and natural stone, such as granite or marble; metals and
alloys, such as aluminium, copper, iron, steel, nonferrous metals,
including surface-finished metals and alloys, such as galvanized
metals and chrome-plated metals; asphalt; bituminous felt;
plastics, such as PVC, ABS, PC, PA, polyester, PMMA, SAN, epoxide
resins, phenolic resins, PUR, POM, PO, PE, PP, EPM, EPDM in
untreated form or surface treated by means of plasma, corona or
flame; particularly PVC, PO (FPO, TPO) or EPDM membranes; coated
substrates, such as varnished tiles, painted concrete and coated
metals.
It can be advantageous to pre-treat the substrate before applying
the membrane, for example by washing, pressure-washing, wiping,
blowing off, grinding and/or applying a primer and/or an
undercoat.
By this method, a waterproof roof structure is obtained comprising
the cured membrane with the incorporated fibre reinforcement
mesh.
The roof structure is preferably part of the roof of a building,
particularly a building from structural and civil engineering,
preferably a house, an industrial building, a hangar, a shopping
center, a sports stadium or the like.
The one-part moisture-curing liquid-applied waterproofing membrane
described herein has a series of advantages. It has low odour, a
long shelf life stability and a low viscosity at low solvent
content, even when containing only about 50 g VOC per liter or
less. Being a one-part system, there is no mixing step required,
which facilitates application. It has a sufficiently long open time
to allow hand application, making the use of special equipment such
as spraying machines unnecessary. Its open time can be adjusted in
a wide range, in particular by the selection and amount of
catalysts. When contacted with moisture, it cures surprisingly fast
to a solid walkable material. After full curing, the membrane is an
elastic material having high strength, elongation and durability.
Preferably it has a tensile strength of at least 3.5 MPa, more
preferably at least 4 MPa, and most preferably at least 5 MPa.
Preferably it has an elongation at break of at least 200%, more
preferably at least 300%, and most preferably at least 350%.
With these properties the membrane is able to protect a building
over a long period of time from water ingress in a broad
temperature range.
EXAMPLES
"Normal climate" means a temperature of 23.+-.1.degree. C. and a
relative atmospheric moisture of 50.+-.5%.
The amine content (total content of free amines and blocked amines,
i.e. aldimino groups) of the prepared aldimines was determined by
titration (with 0.1 N HClO.sub.4 in acetic acid against cristal
violet) and is given in mmol N/g.
1. Used Substances:
TABLE-US-00001 IPDI trimer Isocyanurate of IPDI, 70 weight-% in
solventnaphta 100, NCO content 11.9 wt-% (Desmodur .RTM. Z 4470 SN
from Bayer). Oxazolidine Bis-oxazolidine of the Formula (II b);
equivalent weight 125 g (Incozol .RTM. 4 from Incorez). Aldimine-1
N,N'-bis(2,2-dimethyl-3-lauroyloxypropylidene)-3-
aminomethyl-3,5,5-trimethylcyclohexylamine; with an equivalent
weight of 367 g. Aldimine-2
N,N',N''-tris(2,2-dimethyl-3-lauroyloxypropylidene)-
polyoxypropylene triamine with an average molecular weight of about
1245 g/mol; with an equivalent weight of 449 g/Eq (derived from
Jeffamine .RTM. T-403 from Huntsman). Aldimine-3
N,N'-bis(2,2-dimethyl-3-lauroyloxypropylidene)-
hexamethylene-1,6-diamine; with an equivalent weight of 351 g.
DBTDL Dibutyltin dilaurate (Sigma Aldrich) HALS
Bis-(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate DPK Diphenylcresyl
phosphate (Disflamoll .RTM. DPK from Lanxess). ATH Aluminum
trihydroxide
The Polymer-1 was prepared by reacting 906.1 g polyoxypropylene
diol with an average molecular weight of ca. 1000 g/mol
(Voranol.RTM. 1010 L from Dow), 28.1 g 1,4-butanediol and 514.4 g
isophoronediisocyanate (Vestanat.RTM. IPDI from Evonik) in the
presence of 1.4 g dibutyltin dilaurate (DBTDL) according to known
procedures at 80.degree. C. to obtain an isocyanate-functional
polyurethane polymer with an NCO content of 6.34 weight-%.
The Polymer-2 was prepared by reacting 290.4 g polyoxypropylene
diol with an average molecular weight of ca. 2000 g/mol
(Voranol.RTM. 2000 L from Dow), 838.8 g polyoxypropylene diol with
an average molecular weight of 4000 g/mol (Acclaim.RTM. 4200 from
Bayer), 9.8 g 1,4-butanediol and 361.0 g MDI (Desmodur.RTM. VL 50
from Bayer according to known procedures at 90.degree. C. to obtain
an isocyanate-functional polyurethane polymer with NCO content 5.2
weight-%.
Aldimine-1:
N,N'-bis(2,2-dimethyl-3-lauroyloxypropylidene)-3-aminomethyl-3,5,5-trimet-
hylcyclohexylamin
598 g (2.1 mol) 2,2-dimethyl-3-lauroyloxy-propanal were placed in a
round bottom flask under nitrogen atmosphere. Then 170.3 g (1 mol)
3-aminomethyl-3,5,5-trimethylcyclohexylamine (Vestamin.RTM. IPD
from Evonik) were added under good stirring, followed by removing
the volatile contents at 80.degree. C. and 10 mbar vacuum. The
yield was 732 g of a nearly colourless liquid with an amine content
of 2.73 mmol N/g, corresponding to a calculated aldimine equivalent
weight of approx. 367 g/Eq.
Aldimine-2:
N,N',N''-tris(2,2-dimethyl-3-lauroyloxypropylidene)-polyoxypropylenetriam-
ine
Under the same conditions as given for Aldimine-1, 875 g (3.08 mol)
2,2-dimethyl-3-lauroyloxy-propanal and 440 g (ca. 2.8 mol N)
polyoxypropylenetriamine of average molecular weight of about 440
g/mol (Jeffamine.RTM. T-403 from Huntsman, amine content 6.40 mmol
N/g) were reacted. The yield was 1,264 g of a nearly colourless
liquid with an amine content of 2.23 mmol N/g, corresponding to a
calculated aldimine equivalent weight of approx. 449 g/Eq.
Aldimine-3:
N,N'-bis(2,2-dimethyl-3-lauroyloxypropylidene)-hexamethylene-1,6-diamine
Under the same conditions as given for Aldimine-1, 622 g (2.2 mol)
2,2-dimethyl-3-lauroyloxy-propanal and 166.0 g (1 mol)
hexamethylene-1,6-diamine solution (70 weight-% in water) were
reacted. The yield was 702 g of a nearly colourless liquid with an
amine content of 2.85 mmol N/g, corresponding to a calculated
aldimine equivalent weight of approx. 351 g/Eq.
2. Unfilled One-Part Moisture-Curing Liquid-Applied Waterproofing
Membranes
For each membrane the ingredients given in Table 1 were mixed under
exclusion of moisture in a sealed polypropylene beaker by means of
a centrifugal mixer (SpeedMixer.TM. DAC 150, FlackTek Inc.) until a
homogeneous fluid was obtained.
The membranes were stored in a tightly sealed, moisture-proof can
for 24 hours at ambient temperature and then tested as follows:
To determine the mechanical properties, a two-layer cured film was
prepared for each membrane. To prepare the film, a first layer of
800 .mu.m thickness was applied with a draw down bar and left
curing in normal climate (NC) for 24 hours; then a second layer of
400 .mu.m thickness was applied thereon at an angle of 90.degree.
and again left curing in NC for 24 hours; the two-layer film was
then placed it an oven at 60.degree. C. for 24 hours. After an
additional 24 hours in NC, dumbbells with a length of 75 mm, a
crosspiece length of 30 mm and a crosspiece width of 4 mm were
punched from the film and tensile strength and elongation at break
determined according to DIN EN 53504 at a crosshead speed of 200
mm/min.
The cured free films of each of the membranes were clear,
bubble-free and non-tacky.
The results are given in Table 1.
The liquid-applied membranes Ex-1 to Ex-3 are examples according to
the invention, the liquid-applied membranes Ref-1 and Ref-2 are
comparative examples.
Table 1 shows the influence of different aldimine and oxazolidine
combinations on the mechanical properties of cured unfilled
membranes.
TABLE-US-00002 TABLE 1 Composition (in weight parts) and test
results of the membranes Ex-1 to Ex-3 and Ref-1 to Ref-2 Ref-1 Ex-1
Ex-2 Ex-3 Ref-2 Polymer-1 465.3 465.3 465.3 465.3 465.3 Solvent
.sup.1 176.5 176.5 176.5 176.5 176.5 IPDI trimer 65.2 65.2 65.2
65.2 65.2 Oxazolidine 110.0 88.0 54.8 38.3 -- Aldimine-1 -- 12.9
15.4 23.3 45.0 Aldimine-2 -- 75.1 85.0 128.3 243.0 DBTDL 0.2 0.2
0.2 0.2 0.2 Salicylic acid 0.70 0.8 0.8 0.8 0.8 Aldim./Oxazol.
Ratio .sup.2 0/100 37/63 51/49 70/30 100/0 Tensile Strength [MPa]
12.76 11.5 10.23 9.67 2.27 Elongation at Break [%] 369 531 548 610
526 .sup.1 1-methoxy-2-propylacetate .sup.2 ratio between aldimino
groups and oxazolidino groups
3. Filled Aliphatic One-Part Moisture-Curing Liquid-Applied
Waterproofing Membranes
For each membrane the following ingredients were mixed under
exclusion of moisture in a sealed polypropylene beaker by means of
a centrifugal mixer (SpeedMixer.TM. DAC 150, FlackTek Inc.) until a
homogeneous fluid was obtained:
554.7 weight parts of the Polymer-1,
58.6 weight parts of 1-methoxy-2-propylacetate,
71.5 weight parts of IPDI trimer,
278.9 weight parts of titanium dioxide,
545.3 weight parts of ATH,
213.1 weight parts of barytes,
18.4 weight parts of fumed silica,
26.9 weight parts of carbon black,
10.0 weight parts of HALS,
0.2 weight parts of DBTDL,
0.8 weight parts of salicylic acid and
the ingredients given in Table 2.
The membranes were stored in a tightly sealed, moisture-proof can
for 24 hours at ambient temperature and then tested as follows:
The viscosity was measured with a Brookfield DV-E spindle type
viscometer, spindle n.degree. 5, 30 rpm, at a temperature of
20.degree. C. "Initial" means the viscosity measured 24 hours after
mixing the ingredients. "28 d 40.degree. C." means the viscosity
measured after an additional storage time of 28 days at 40.degree.
C. "42 d 40.degree. C." means the viscosity measured after an
additional storage time of 42 days at 40.degree. C.
Cure speed ("BK drying time") was determined at 20.degree. C./45%
relative humidity using a Beck-Koller drying time recorder
according to ASTM D5895. The result for stage 2 indicates
approximately the skinning time of the membrane.
Tensile strength and elongation at break were measured as described
for the unfilled membranes of Table 1.
The cured free films of each of the membranes were bubble-free and
non-tacky.
The results are given in Table 2.
The liquid-applied membranes Ex-4 to Ex-6 are examples according to
the invention, the liquid-applied membranes Ref-3 and Ref-4 are
comparative examples.
Table 2 shows filled, low-VOC membranes based on a polyurethane
polymer obtained from aliphatic polyisocyanate.
TABLE-US-00003 TABLE 2 Composition (in weight parts) and test
results of the examples Ex-4 to Ex-6 and Ref-3 to Ref-4 Ref-3 Ex-4
Ex-5 Ex-6 Ref-4 Ingredients Given Above 1'778.4 1'778.4 1'778.4
1'778.4 1'778.4 DPK 524.6 464.8 446.9 428.9 405.0 Oxazolidine 120.6
96.4 80.0 55.9 -- Aldimine-1 -- 14.2 22.5 34.0 63.6 Aldimine-2 --
82.3 128.2 187.4 356.1 Aldim./Oxazol. Ratio .sup.2 0/100 37/63
52/48 70/30 100/0 Viscosity [mPa s], initial 6'400 5'600 5'200
5'300 4'000 Viscosity [mPa s], 28 d 40.degree. C. 14'240 11'300
9'100 7'400 4'900 BK Drying Time Stage 2 >12 5.5 6 7.5 6.5 [h]
Stage 3 >12 11.5 10.5 8 7.5 Stage 4 >12 >12 >12 >12
>12 Tensile Strength [MPa] 4.99 6.49 5.38 4.40 3.40 Elongation
at Break [%] 244 349 322 367 432 .sup.2 ratio between aldimino
groups and oxazolidino groups
4. Filled Aromatic One-Part Moisture-Curing Liquid-Applied
Waterproofing Membranes
For each membrane the following ingredients were mixed under
exclusion of moisture in a sealed polypropylene beaker by means of
a centrifugal mixer (SpeedMixer.TM. DAC 150, FlackTek Inc.) until a
homogeneous fluid was obtained:
652.1 weight parts of the Polymer-2,
569.5 weight parts of xylene,
160.8 weight parts of titanium dioxide,
221.1 weight parts of barytes,
881.9 weight parts of chalk,
40.4 weight parts of fumed silica,
202.0 weight parts of diisodecyl phthalate and
the ingredients given in Table 3.
The membranes were stored in a tightly sealed, moisture-proof can
for 24 hours at ambient temperature and then tested in the same way
as the filled aliphatic membranes of Table 2.
The test results are given in Table 3.
The membranes Ex-7 and Ex-8 are examples according to the
invention, the membranes Ref-5 and Ref-6 are comparative
examples.
Table 3 shows filled membranes based on a polyurethane polymer
obtained from aromatic polyisocyanate.
TABLE-US-00004 TABLE 3 Composition (in weight parts) and test
results of the examples Ex-7, Ex-8, Ref-5 and Ref-6 Ref-5 Ex-7 Ex-8
Ref-6 Ingredients Given Above 2'727.8 2'727.8 2'727.8 2'727.8
Oxazolidine 91.3 45.7 45.7 68.5 Aldimine-1 -- 45.7 -- -- Aldimine-3
-- -- 45.7 22.8 Aldim./Oxazol. Ratio .sup.1 0/100 41/59 42/58 19/81
Viscosity [mPa s], initial 9'500 8'500 9'000 10'000 Viscosity [mPa
s], 42 d 40.degree. C. 26'000 18'000 19'000 25'000 Tensile strength
[MPa] 4.1 3.9 3.6 4.0 Elongation at break [%] 178 223 242 204
.sup.1 ratio between aldimino groups and oxazolidino groups
* * * * *